1 files changed, 110 insertions, 0 deletions
diff --git a/host/lib/include/uhdlib/transport/frame_reservation_mgr.hpp b/host/lib/include/uhdlib/transport/frame_reservation_mgr.hpp
new file mode 100644
index 000000000..f0dd853a4
--- /dev/null
+++ b/host/lib/include/uhdlib/transport/frame_reservation_mgr.hpp
@@ -0,0 +1,110 @@
+//
+// Copyright 2019 Ettus Research, a National Instruments brand
+//
+// SPDX-License-Identifier: GPL-3.0-or-later
+//
+
+#ifndef INCLUDED_UHDLIB_TRANSPORT_FRAME_RESERVATION_MGR_HPP
+#define INCLUDED_UHDLIB_TRANSPORT_FRAME_RESERVATION_MGR_HPP
+
+#include <uhd/config.hpp>
+#include <uhd/exception.hpp>
+#include <uhdlib/transport/link_if.hpp>
+#include <unordered_map>
+
+namespace uhd { namespace transport {
+
+/*!
+ * Helper class to keep track of the number of frames reserved from a pair of links
+ */
+class frame_reservation_mgr
+{
+public:
+    struct frame_reservation_t
+    {
+        recv_link_if::sptr recv_link;
+        size_t num_recv_frames = 0;
+        send_link_if::sptr send_link;
+        size_t num_send_frames = 0;
+    };
+
+    void register_link(const recv_link_if::sptr& recv_link)
+    {
+        if (_recv_tbl[recv_link.get()] != 0) {
+            throw uhd::runtime_error("Recv link already attached to I/O service");
+        }
+        _recv_tbl[recv_link.get()] = 0;
+    }
+
+    void register_link(const send_link_if::sptr& send_link)
+    {
+        if (_send_tbl[send_link.get()] != 0) {
+            throw uhd::runtime_error("Send link already attached to I/O service");
+        }
+        _send_tbl[send_link.get()] = 0;
+    }
+
+    void unregister_link(const recv_link_if::sptr& recv_link)
+    {
+        auto link_ptr = recv_link.get();
+        UHD_ASSERT_THROW(_recv_tbl.count(link_ptr) != 0);
+        _recv_tbl.erase(link_ptr);
+    }
+
+    void unregister_link(const send_link_if::sptr& send_link)
+    {
+        auto link_ptr = send_link.get();
+        UHD_ASSERT_THROW(_send_tbl.count(link_ptr) != 0);
+        _send_tbl.erase(link_ptr);
+    }
+
+    void reserve_frames(const frame_reservation_t& reservation)
+    {
+        if (reservation.recv_link) {
+            const size_t rsvd_frames = _recv_tbl.at(reservation.recv_link.get());
+            const size_t capacity    = reservation.recv_link->get_num_recv_frames();
+            if (rsvd_frames + reservation.num_recv_frames > capacity) {
+                throw uhd::runtime_error(
+                    "Number of frames requested exceeds link recv frame capacity");
+            }
+
+            recv_link_if* link_ptr = reservation.recv_link.get();
+            _recv_tbl[link_ptr]    = rsvd_frames + reservation.num_recv_frames;
+        }
+
+        if (reservation.send_link) {
+            const size_t rsvd_frames = _send_tbl.at(reservation.send_link.get());
+            const size_t capacity    = reservation.send_link->get_num_send_frames();
+            if (rsvd_frames + reservation.num_send_frames > capacity) {
+                throw uhd::runtime_error(
+                    "Number of frames requested exceeds link send frame capacity");
+            }
+
+            send_link_if* link_ptr = reservation.send_link.get();
+            _send_tbl[link_ptr]    = rsvd_frames + reservation.num_send_frames;
+        }
+    }
+
+    void unreserve_frames(const frame_reservation_t& reservation)
+    {
+        if (reservation.recv_link) {
+            const size_t rsvd_frames = _recv_tbl.at(reservation.recv_link.get());
+            recv_link_if* link_ptr   = reservation.recv_link.get();
+            _recv_tbl[link_ptr]      = rsvd_frames - reservation.num_recv_frames;
+        }
+
+        if (reservation.send_link) {
+            const size_t rsvd_frames = _send_tbl.at(reservation.send_link.get());
+            send_link_if* link_ptr   = reservation.send_link.get();
+            _send_tbl[link_ptr]      = rsvd_frames - reservation.num_send_frames;
+        }
+    }
+
+private:
+    std::unordered_map<recv_link_if*, size_t> _recv_tbl;
+    std::unordered_map<send_link_if*, size_t> _send_tbl;
+};
+
+}} // namespace uhd::transport
+
+#endif /* INCLUDED_UHDLIB_TRANSPORT_FRAME_RESERVATION_MGR_HPP */